In such a method, which is used in example for fabricating a connecting rod out of composite material, a mandrel is used that mainly constitutes a support on which the layers of braided reinforcing fibers are formed. The braided layers fit closely to the outside shape of the mandrel when they are applied thereon, such that the final connecting rod has a shape that corresponds to a desired shape.
The layers of reinforcing fibers are applied on the mandrel with a braiding machine of the same type as the machine referenced 1 in FIG. 1.
The mandrel 2 is then installed in the machine 1, which essentially comprises a ring 3 carrying two series of reels of reinforcing fibers. The reinforcing fibers 4 meet on the mandrel that extends along an axis AX, in a region of convergence situated at a certain distance from the ring 3, so that the reinforcing fibers together define a conical shape.
The launching of a braiding cycle causes firstly the mandrel 2 to be moved relative to the ring 3 along the axis AX, and secondly the reels of the first series and the reels of the second series to be moved along the circumference of the ring in opposite directions.
The reels of the first series follow a first sinusoidal path extending along the circumference of the ring, and the reels of the second series follow a second sinusoidal path also extending along the circumference of the ring, and crossing the first path.
In practice, the reels of the first series and the reels of the second series alternate along the circumference of the ring. In operation, the reels of the first series and the reels of the second series turn in opposite directions while following their sinusoidal paths, so that they cross without interfering with one another in order to form the braid.
The angle of inclination θ of the fibers in the layer of braided fibers relative to the longitudinal axis AX, is thus determined by the forward speed Vm of the mandrel along the axis AX and by the speed of rotation ωc of the reels around the axis AX, and also by the diameter Dm of the mandrel, in accordance with the following relationship:tan(θ)=π·Dm·ωc/Vm 
For a given part, the forward speed of the mandrel and the speed of rotation of the reels are adjusted so that the fibers are braided while being inclined at a predetermined angle θ such as 30° or 60° relative to the axis AX. Several passes may be performed in order to build up a plurality of superposed layers of braided fibers around the mandrel.
The assembly constituted by the mandrel and the various layers of braided fibers that it carries is then placed in a mold. Resin is then injected in order to impregnate the layers of fibers, after which the resin is polymerized, e.g. by heating, so that the assembly constituted by the layers of fibers and the resin constitutes a rigid whole.
That method makes it possible to fabricate a connecting rod having mechanical qualities that are substantially identical in its various regions. However, that method is not suitable for acting in a competitive manner to produce connecting rods such as the connecting rods 6 and 7 shown in FIGS. 2 and 3, since their looked-for mechanical qualities are different depending on whether consideration is given to their ends or else to their main bodies.
Specifically, the ends comprise lugs that constitute force-insertion zones, and they are consequently subjected to multidirectional mechanical stresses that are very different from and much higher than the stresses to which the body of the connecting rod is subjected, which mechanical stresses are mainly longitudinal.
In practice, it is necessary to add material at the ends in order to increase the mechanical strength and the fatigue behavior in those regions. Nevertheless, such existing solutions for adding material locally are complex and very expensive to perform.